1. Field of the Invention
The present invention relates to a filter system in use for filtration of liquids of either food or industrial materials containing liquid and solid components, and more particularly to a novel scraper filter system suitable for processing highly viscous liquids or slurries.
2. Description of the Prior Art
In general, filtration of highly viscous substances such as liquids or slurries of soybean, ground fish meat, or devil's tongue starch has been usually performed through the multi-step filtration including filters having gradually decreased filter openings or using mesh filters.
Various forms of scraper filters are known. However, no filters by which filtered residue can be effectively separated as complete filter cakes, are known.
Previously, the applicant disclosed an improved technology on liquid separation in Japanese patent application No. 32874/1989.
The filter system disclosed therein comprises a cylindrical filter element, a cylindrical drum, and a spiral impeller provided with scraper means. The scraper means disclosed therein comprises a plurality of support rods retained to the spiral impeller for supporting scrapers, which engage with the internal surface of the filter element.
In the case of the filter system, since the scraper means is formed separately from the spiral impeller, further including support stays, the filtered residue generated from a sticky liquid was not sufficiently removed to cause blinding and stoppage of filtration.